Methods according to the generic kind are used, in particular for medical purposes, in the field of computer radiography (CR). In this connection, X-ray pictures are recorded in a phosphor layer by storing X-ray radiation passing through an object, for example a patient, as a latent image in the phosphor layer. To read out the stored image, the phosphor layer is irradiated with stimulation light and excited to emit emission light that is sensed by an optical detector and converted into electrical signals. If required, the electrical signals can be processed further and displayed on a monitor or outputted on a suitable output device, such as, for example, a printer.
EP 1 319 963 A1 describes a method in which a detector is driven in a forward-travel direction over a phosphor layer and, during this process, senses the emission light emitted by individual row-type regions of the phosphor layer. The emission light emitted by a row-type region is sensed during an adjustable integration time. The width of the row-type region is determined in the forward-travel direction by the integration time on the basis of the continuous forward travel of the detector during the integration time. In particular, a longer integration time is set at low intensities of the emission light in order to increase the width of the row-type regions. This can reduce the proportion of the so-called read-out noise in the detector signal and, consequently, improve the signal/noise ratio.
It has, however, been found that a longer integration time does not result in a better signal/noise ratio in all application cases. On the contrary, in certain cases, the noise may increase with integration time in relation to the signal of the sensed emission light, which results overall in a poorer signal/noise ratio.
Since the detector scans, while sensing the emission light during a longer integration time, a correspondingly wider region of the phosphor layer in the forward-travel direction than in the case of a shorter integration time, detailed information items are, in addition, lost within the region in the case of the method according to the prior art. This effect is also described as movement-induced blurring.